About The Role What if your C# expertise could directly shape the infrastructure powering the next generation of AI? We're looking for a Senior C# Full-Stack Engineer to build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on every day.

This is a fully remote contract role working on real production systems — not toy projects. You'll be embedded in high-impact engineering workflows alongside data, research, and infrastructure teams pushing the frontier of AI development.

- Organization: Alignerr
- Type: Hourly Contract
- Location: Remote
- Commitment: 20–40 hours/week

What You'll Do

- Design, build, and optimize high-performance C# systems that power AI data pipelines and evaluation workflows
- Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control
- Improve reliability, performance, and safety across existing production C# codebases
- Collaborate with data, research, and engineering teams to support model training and evaluation infrastructure
- Identify bottlenecks and edge cases in data and system behavior — then implement scalable, production-ready fixes
- Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are





- Native or fluent English speaker with clear written and verbal communication skills
- Experienced full-stack developer with a strong systems programming foundation
- 3–5+ years of professional experience writing production C# code, with familiarity in modern standards and best practices
- Strong background in performance optimization, concurrency (threading, atomics), and memory safety
- Able to commit 20–40 hours per week consistently
- Self-directed and comfortable working autonomously in a remote environment

Nice to Have

- Prior experience with data annotation, data quality pipelines, or evaluation systems
- Familiarity with AI/ML workflows, model training, or benchmarking infrastructure
- Experience with distributed systems or internal developer tooling
- Exposure to C++17/C++20 or other systems-level languages

Why Join Us

- Work directly with leading AI labs on production systems that shape next-generation models
- Fully remote and versátil — structure your work around your life
- Freelance autonomy with the depth and impact of meaningful, long-term technical work
- Contribute to AI infrastructure that has real, lasting consequences for how models are built and evaluated
- Potential for ongoing work and contract extension as new projects launch

📌 Senior C# Full-Stack Engineer — AI Data & Infrastructure (México)
🏢 Alignerr
📍 México